\(15^{th}\) BEEN Conference - LUISS, 23 January 2026
DEM-CEEL, University of Trento
DEM, University of Trento
DEM-CEEL, University of Trento
Do non-binding promises increase cooperation in a five-player sequential chain of cooperation?
Mechanisms:
How likely is a player to send a pass promise?
How likely is a player to cooperate after receiving a promise?
Key idea
In sequential chains, policy leverage may lie in eliciting explicit commitments, not in richer communication.
Centipede cooperation
Promises and cooperation
| Treatment | Promise (available?) | Mandatory promise (Take/Pass) | Fee for sending message |
|---|---|---|---|
| Baseline (B) | ✗ | ✗ | ✗ |
| Cheap Talk (C) | ✓ | ✓ | ✗ |
| Voluntary (V) | ✓ | ✗ | ✗ |
| Fee (F) | ✓ | ✗ | ✓ |
- H1 (Promises): take-up of pass promises differs by regime.
- H1a: Pass promises same in Voluntary and Cheap Talk.
- H1b: Pass promises lower in Fee than Voluntary.
- H2 (Cooperation): any promise regime increases Pass vs Baseline.
- H3 (Credibility/response):
- H3a: Pass promise triggers more passing in Voluntary than Cheap Talk (silence makes it “less coerced”).
- H3b: Pass promise triggers more passing in Fee than Voluntary (fee increases credibility).
Takeaway
Aggregate cooperation is driven primarily by the prevalence of explicit commitments, not by large credibility shifts conditional on a promise.
Casal, Mittone, Ploner — Promises in Sequential Cooperation